A semiconductor element such as a light-emitting diode is manufactured by forming a semiconductor film, for example, a GaN-based compound semiconductor film, by epitaxial crystal growth on a principal surface (polished surface) of a semiconductor element substrate made of sapphire or the like, and forming electrodes and others. The semiconductor layer is formed heating the semiconductor element substrate, and is thereafter cooled to room temperature. Therefore, a warp that is convex to the semiconductor film side is produced during cooling due to a difference in thermal expansion between the semiconductor element substrate and the semiconductor film.
In order to correct this warp, for example, cited document 1 discloses a technique for correcting a warp using a large-sized press device that is for pressing at a pressure of 4.9×104 to 4.9×106 Pa. Moreover, cited document 2 discuses a technique for correcting a warp through modification of the interior of a sapphire substrate by converging and scanning pulsed laser light on the interior.